A few weeks back

A few weeks back I reported — and took a little heat for reporting — that South Dakota’s closely-watched Thune-Johnson Senate race might be looking a bit better for Tim Johnson than some people in DC realized. The upshot of the post was that key Republicans in DC weren’t entirely sure Thune’s team was up to snuff, or at least up to taking on the campaign team Tom Daschle … errr, I mean, Tim Johnson had put together.

One of DC’s sharpest political observers subsequently told me that he thought it was less that Thune’s team was weak than that Johnson’s team was just so strong, the strongest campaign team in any Democratic campaign in the country, perhaps any campaign in either party. But, whether in relative terms or absolute ones, I stick by the story.

In any case, since then there have been a run of small news items in the state that have make it look like the Johnson campaign might be a bit stronger than some outside the state realized. In recent weeks the Thune campaign has opened up with a fusillade of negative ads. The Johnson folks ran them too. But mainly stuff from outside groups and in any case, not to the same extent.

More recently rumors have spread through the state that the Thune campaign’s most recent internal polling had him behind Johnson for the first time ever. Not by much. Well within the margin of error. But behind.

Now, I haven’t been able to get to the bottom of those rumors. Republicans officials have denied it to me flatly, if not altogether convincingly. But today the Sioux Fall’s Argus Leaderreports that a new Johnson campaign internal poll (which of course they’ve obligingly released) has Johnson up by two points — 49% to 47%. That’s the first poll that’s ever had Johnson ahead in this race, to the best of my knowledge.

Now, a few necessary points. This a hardly a big lead. In fact, it’s statistically insignificant, since it’s in the margin of error. But put it together with the run of polls over recent months and it’s hard not to get the impression that Johnson has the momentum in this race. That may explain that round of negative ads from Thune.

One other point about the poll deserves mention. More striking than the tightness of this race is the extremely small percentage of undecideds. Here’s why this is important. Many Republicans have looked at this race and said that Johnson’s in trouble because he’s not over 50%. Normally, this would be true: Incumbents who poll under 50% are by definition in trouble because the voters know the incumbent and polling under 50% means most voters don’t think the incumbent deserves reelection. They’re just not sure they’re willing to take a chance on the challenger. But history says most opt to take that chance.

Democrats have argued that this logic doesn’t apply in this case. Their reasoning is that Johnson and Thune are really both incumbents since Johnson represents the whole state in the Senate and Thune currently represents the whole state in the House. That’s a pretty good argument. And this poll, I think, tends to show that it’s also true.